1. Field of the Invention
This invention relates to an apparatus and method for recovering bituminous products from tar sands.
2. The Prior Art
Tar sands are naturally occurring deposits which are generally constituted of bulk inorganic particles such as siliceous sands which are impregnated with a matrix of heavy petroleum or bitumen containing various types of hydrocarbons. Historically, the term tar sand was applied to these deposits because of their similarity in appearance to asphaltic compositions, although they have also been described variously as oil sands and bituminous sands.
Tar sand deposits are generally found in significantly large reserves such as those of the Athabasca tar sand deposits located near Ft. McMurray, Canada. Tar sand deposits are also found, for example, near Vernal, Green River, and Sunnyside, Utah. These tar sand deposits contain significant reserves of potentially recoverable bituminous products.
Various separation processes have been proposed for separating the bituminous products from the tar sand by treatment with (a) water, (b) water/surfactant mixtures, (c) solvents, (d) heat, and (e) combinations of the foregoing. Some of these processes are set forth in U.S. Pat. Nos. 1,497,607; 1,514,113; 2,871,180; 2,965,557; 3,161,581; 3,392,105; 3,553,099; 3,605,975; 3,847,789; 3,856,474; 3,875,046; 3,893,907. These references disclose processes which variously require some form of crushing, grinding or otherwise mechanically comminuting the agglomerated tar sands to a finely divided state in order to obtain a more thorough exposure of the bituminous matrix material to the action of the recovery technique. However, grinding or crushing is difficult and expensive because of the excessive equipment wear caused by the siliceous material which has a hardness greater than most components of the tar sand handling equipment. This feature is particularly important where tar sand is communited to relatively finely divided particles to increase exposure of the bituminous matrix to the recovery process.
It would therefore be an advancement in the art to provide a method and apparatus for disintegrating agglomerated masses of tar sand without subjecting the mechanical equipment to excessive wear. It would be another advancement in the art to provide an apparatus and method whereby advantage is taken of the abrasive nature of the tar sand masses to cause the tar sand masses to be suspended and agitated in a liquid to thereby reduce themselves to granules of sand to increase exposure of the bituminous products. It would be an even further advancement in the art to provide a liquid solvent and a high shear environment in the liquid whereby the bituminous matrix material is rapidly stripped from the granules of sand. Such an apparatus and method is disclosed herein.